CN111040118B - Waterborne polyurethane for microfiber leather as well as preparation method and application of waterborne polyurethane - Google Patents

Waterborne polyurethane for microfiber leather as well as preparation method and application of waterborne polyurethane Download PDF

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CN111040118B
CN111040118B CN202010018751.1A CN202010018751A CN111040118B CN 111040118 B CN111040118 B CN 111040118B CN 202010018751 A CN202010018751 A CN 202010018751A CN 111040118 B CN111040118 B CN 111040118B
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microfiber leather
waterborne polyurethane
weight
microfiber
leather
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CN111040118A (en
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易杰
薛斌
袁惠敏
时圣明
代正伟
李书卿
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Shanghai Piyou New Material Co ltd
Jiaxing University
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Shanghai Piyou New Material Co ltd
Jiaxing University
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    • CCHEMISTRY; METALLURGY
    • C08ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08GMACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G18/00Polymeric products of isocyanates or isothiocyanates
    • C08G18/06Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
    • C08G18/28Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
    • C08G18/65Low-molecular-weight compounds having active hydrogen with high-molecular-weight compounds having active hydrogen
    • C08G18/66Compounds of groups C08G18/42, C08G18/48, or C08G18/52
    • C08G18/6666Compounds of group C08G18/48 or C08G18/52
    • C08G18/6692Compounds of group C08G18/48 or C08G18/52 with compounds of group C08G18/34
    • CCHEMISTRY; METALLURGY
    • C08ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08GMACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G18/00Polymeric products of isocyanates or isothiocyanates
    • C08G18/06Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
    • C08G18/28Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
    • C08G18/30Low-molecular-weight compounds
    • C08G18/32Polyhydroxy compounds; Polyamines; Hydroxyamines
    • C08G18/3203Polyhydroxy compounds
    • C08G18/3206Polyhydroxy compounds aliphatic
    • CCHEMISTRY; METALLURGY
    • C08ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08GMACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G18/00Polymeric products of isocyanates or isothiocyanates
    • C08G18/06Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
    • C08G18/28Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
    • C08G18/30Low-molecular-weight compounds
    • C08G18/34Carboxylic acids; Esters thereof with monohydroxyl compounds
    • C08G18/348Hydroxycarboxylic acids
    • CCHEMISTRY; METALLURGY
    • C08ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08GMACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G18/00Polymeric products of isocyanates or isothiocyanates
    • C08G18/06Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
    • C08G18/28Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
    • C08G18/40High-molecular-weight compounds
    • C08G18/48Polyethers
    • C08G18/4854Polyethers containing oxyalkylene groups having four carbon atoms in the alkylene group
    • DTEXTILES; PAPER
    • D06TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
    • D06NWALL, FLOOR, OR LIKE COVERING MATERIALS, e.g. LINOLEUM, OILCLOTH, ARTIFICIAL LEATHER, ROOFING FELT, CONSISTING OF A FIBROUS WEB COATED WITH A LAYER OF MACROMOLECULAR MATERIAL; FLEXIBLE SHEET MATERIAL NOT OTHERWISE PROVIDED FOR
    • D06N3/00Artificial leather, oilcloth or other material obtained by covering fibrous webs with macromolecular material, e.g. resins, rubber or derivatives thereof
    • D06N3/12Artificial leather, oilcloth or other material obtained by covering fibrous webs with macromolecular material, e.g. resins, rubber or derivatives thereof with macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds, e.g. gelatine proteins
    • D06N3/14Artificial leather, oilcloth or other material obtained by covering fibrous webs with macromolecular material, e.g. resins, rubber or derivatives thereof with macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds, e.g. gelatine proteins with polyurethanes
    • DTEXTILES; PAPER
    • D06TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
    • D06NWALL, FLOOR, OR LIKE COVERING MATERIALS, e.g. LINOLEUM, OILCLOTH, ARTIFICIAL LEATHER, ROOFING FELT, CONSISTING OF A FIBROUS WEB COATED WITH A LAYER OF MACROMOLECULAR MATERIAL; FLEXIBLE SHEET MATERIAL NOT OTHERWISE PROVIDED FOR
    • D06N2209/00Properties of the materials
    • D06N2209/16Properties of the materials having other properties
    • D06N2209/1607Degradability
    • DTEXTILES; PAPER
    • D06TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
    • D06NWALL, FLOOR, OR LIKE COVERING MATERIALS, e.g. LINOLEUM, OILCLOTH, ARTIFICIAL LEATHER, ROOFING FELT, CONSISTING OF A FIBROUS WEB COATED WITH A LAYER OF MACROMOLECULAR MATERIAL; FLEXIBLE SHEET MATERIAL NOT OTHERWISE PROVIDED FOR
    • D06N2209/00Properties of the materials
    • D06N2209/16Properties of the materials having other properties
    • D06N2209/1685Wear resistance
    • DTEXTILES; PAPER
    • D06TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
    • D06NWALL, FLOOR, OR LIKE COVERING MATERIALS, e.g. LINOLEUM, OILCLOTH, ARTIFICIAL LEATHER, ROOFING FELT, CONSISTING OF A FIBROUS WEB COATED WITH A LAYER OF MACROMOLECULAR MATERIAL; FLEXIBLE SHEET MATERIAL NOT OTHERWISE PROVIDED FOR
    • D06N2211/00Specially adapted uses
    • D06N2211/12Decorative or sun protection articles
    • D06N2211/28Artificial leather

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  • Chemical Kinetics & Catalysis (AREA)
  • Health & Medical Sciences (AREA)
  • Medicinal Chemistry (AREA)
  • Polymers & Plastics (AREA)
  • Organic Chemistry (AREA)
  • Dispersion Chemistry (AREA)
  • Engineering & Computer Science (AREA)
  • Textile Engineering (AREA)
  • Synthetic Leather, Interior Materials Or Flexible Sheet Materials (AREA)

Abstract

The invention discloses waterborne polyurethane for microfiber leather, a preparation method and application thereof, and relates to the technical field of novel materials. According to the waterborne polyurethane for the microfiber leather and the preparation method thereof, by designing the process flow, the waterborne polyurethane for the microfiber leather is synthesized by adopting the primary chain extension process in acetone and the secondary chain extension process in deionized water, the synthesized waterborne polyurethane for the microfiber leather has high storage stability and extremely high hydrolysis resistance, the technical problems of poor stability and general water resistance caused by the fact that the waterborne polyurethane is easy to gel can be solved, and the waterborne polyurethane for the microfiber leather is applied to the preparation process of the microfiber leather, so that the prepared microfiber leather has the advantages of wear resistance, stability, environmental protection and the like.

Description

Waterborne polyurethane for microfiber leather as well as preparation method and application of waterborne polyurethane
Technical Field
The invention relates to the technical field of novel materials, and particularly relates to waterborne polyurethane for microfiber leather, and a preparation method and application thereof.
Background
Superfine fiber polyurethane synthetic leather, namely superfine fiber leather, is prepared by preparing three-dimensional network structure non-woven fabric by needling superfine fiber short fibers and carrying out processes such as polyurethane resin impregnation, fiber splitting, after finishing and the like. The microfiber leather has excellent water vapor permeability, aging resistance and wear resistance, and has gradually replaced real leather. The impregnation process of the microfiber leather is to uniformly distribute polyurethane in gaps of the non-woven fabric, namely the performance of the polyurethane directly influences the use performance of the microfiber leather. However, almost all the resin used in the current microfiber leather impregnation process is solvent type polyurethane, which causes environmental pollution and resource waste, and the solvent in the microfiber leather is volatilized for a long time to harm the body, so the solvent type polyurethane is limited to be applied to the microfiber leather.
The waterborne polyurethane takes water as a dispersion medium, and has the advantages of no solvent discharge, environmental protection and the like, so that the preparation of the waterborne polyurethane-based microfiber leather is a trend of the microfiber leather industry. When the non-woven fabric (polyester/water-soluble polyester (PET/COPET) or polyamide/water-soluble polyester (PA 6/COPET)) is soaked in the water-based polyurethane, after the non-woven fabric is solidified at high temperature, the non-woven fabric is dissolved by an alkali weight reduction fiber opening process, so that the non-woven fabric has the micropore structure of natural leather.
The alkali weight reduction fiber opening process has long-term high-temperature and high-alkali effects, has extremely high requirements on the water resistance of the waterborne polyurethane, and compared with solvent-based polyurethane, the waterborne polyurethane has the problems of poor water resistance, low solid content and low drying speed, so that the application of the waterborne polyurethane in microfiber leather is restricted. In order to improve the water resistance of the waterborne polyurethane, the Chinese patent CN102432814A introduces epoxy resin for modification to improve the water resistance of the waterborne polyurethane; chinese patent CN101074278 uses diisocyanate and trihydric alcohol to synthesize hyperbranched polyurethane to improve the water resistance.
In the process of implementing the invention, the inventor finds that the related art has at least the following problems:
in order to improve the water resistance of the waterborne polyurethane in the prior art, a cross-linking structure is required to be introduced to limit the chain segment movement, but the gel phenomenon of the waterborne polyurethane is easily caused by improper control of the dosage of a cross-linking agent and reaction conditions, so that the stability of the waterborne polyurethane is poor and the water resistance is general.
Disclosure of Invention
Aiming at the problems in the prior art, the invention provides the aqueous polyurethane for the microfiber leather and the preparation method and the application thereof. The technical scheme of the invention is as follows:
according to a first aspect of the embodiment of the invention, a preparation method of waterborne polyurethane for microfiber leather is provided, which is characterized by comprising the following steps:
(1) blending pentaerythritol and diisocyanate to obtain a first reaction solution, reacting the first reaction solution at 80-90 ℃ for 1-2 h, cooling to 20-25 ℃, adding ethylenediamine ethanesulfonic acid sodium salt into the first reaction solution, and reacting for 2-3 h to prepare a hydrophilic cross-linking agent, wherein the dosage ratio of the pentaerythritol to the diisocyanate to the ethylenediamine ethanesulfonic acid sodium salt is 1 mol: 4 mol;
(2) blending 10-50 parts by weight of macromolecular dihydric alcohol, 2-6 parts by weight of micromolecular dihydric alcohol, 20-60 parts by weight of diisocyanate and 0.2-0.4 part by weight of catalyst to obtain a second reaction solution, reacting the second reaction solution at 60-90 ℃ for 3-4 hours, adding 1-5 parts by weight of micromolecular hydrophilic compound, continuing to react at 60-90 ℃ for 1-2 hours, cooling the second reaction solution to 20-30 ℃, slowly adding 1-15 parts by weight of hydrophilic cross-linking agent, reacting for 1-2 hours, adding 0.5-4 parts by weight of neutralizing agent, reacting for 0.5-1 hour, cooling the second reaction solution to 5-10 ℃, adding 100-250 parts by weight of deionized water, stirring at 2500-3000 r/min for 3-5 min, slowly dropwise adding 1-15 parts by weight of hydrophilic cross-linking agent, stirring at the speed of 2500-3000 r/min for 30min, and then carrying out distillation treatment to prepare the waterborne polyurethane for microfiber leather with the solid content of 25-40%.
In a preferred embodiment, before blending, the macromolecular diol and the small molecular diol are respectively subjected to vacuum pumping dehydration treatment at 120-130 ℃ for 3-5 h, so that the water content of the macromolecular diol and the small molecular diol is less than 0.02%, and the vacuum degree adopted in the vacuum pumping dehydration treatment process is-0.08-0.10 MPa.
In a preferred embodiment, the diisocyanate is at least one of isophorone diisocyanate, IPDI, or 1, 6-hexamethylene diisocyanate, HDI.
In a preferred embodiment, the small molecule diol is at least one of ethylene glycol, 1, 4-butanediol, 2-methyl-1, 3-propanediol, diethylene glycol, and 1, 6-hexanediol.
In a preferred embodiment, the macrodiol is at least one of polypropylene oxide polyol PPG, polytetrahydrofuran ether polyol PTMG, polyethylene glycol PEG and polycarbonate polyol PCD, and the small molecule hydrophilic compound is at least one of dimethylolbutyric acid and dimethylolpropionic acid.
In a preferred embodiment, the catalyst is at least one of dibutyltin dilaurate, bismuth isooctanoate, and bismuth laurate.
In a preferred embodiment, the neutralizing agent is at least one of triethylamine, triethanolamine, tert-butylamine.
According to the second aspect of the embodiment of the invention, the waterborne polyurethane for microfiber leather is prepared by any preparation method of the waterborne polyurethane for microfiber leather, the storage stability of the waterborne polyurethane for microfiber leather is more than or equal to 6 months, the tensile strength of the waterborne polyurethane is more than or equal to 10MPa, the elongation at break of the waterborne polyurethane is 140% -190%, and the yellowing resistance of the waterborne polyurethane is 5 level.
According to a third aspect of the embodiments of the present invention, there is provided an application of the aqueous polyurethane for microfiber leather as described above, the aqueous polyurethane for microfiber leather is applied to preparation of microfiber leather, and a preparation method of the microfiber leather includes:
adjusting the solid content of the waterborne polyurethane for the microfiber leather to be 20-30%, and uniformly permeating the waterborne polyurethane for the microfiber leather into the non-woven fabric by adopting an impregnation process, wherein the impregnation process parameters comprise: the pressure of the compression roller is 2-4 MPa, and the dipping temperature is 40-55 ℃;
drying the non-woven fabric permeated with the waterborne polyurethane for the microfiber leather, putting the non-woven fabric into a NaOH solution with the concentration of 15-25%, opening the microfiber at 90-100 ℃ for 30-60 min, and performing after-treatment to obtain the microfiber leather.
According to a fourth aspect of the embodiment of the invention, the microfiber leather is prepared by the preparation method of the microfiber leather, and the moisture permeability of the microfiber leather is 480-610 mg/10cm2D, the tearing strength is 70.8-79.5N/mm, and the yellowing resistance is grade 5.
Compared with the prior art, the waterborne polyurethane for microfiber leather, and the preparation method and the application thereof provided by the invention have the following advantages:
the aqueous polyurethane for microfiber leather, provided by the invention, is synthesized by a primary chain extension process in acetone and a secondary chain extension process in deionized water, and has the advantages of high storage stability, strong hydrolysis resistance, capability of solving the technical problems of poor stability and general water resistance caused by the fact that the aqueous polyurethane for microfiber leather is easy to gel, and capability of ensuring that the prepared microfiber leather has the advantages of wear resistance, stability, environmental friendliness and the like when the aqueous polyurethane is applied to a microfiber leather preparation process.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and together with the description, serve to explain the principles of the invention.
FIG. 1 is a process flow diagram illustrating a method for preparing waterborne polyurethane for microfiber leather according to one exemplary embodiment,
FIG. 2 is a schematic diagram illustrating the synthesis of a waterborne polyurethane for microfiber leather according to an exemplary embodiment.
FIG. 3 is a method flow diagram illustrating a method of making microfiber leather in accordance with an exemplary embodiment.
FIG. 4 is a broken line diagram of water absorption rate of the waterborne polyurethane for microfiber leather in different chain extension modes.
Detailed Description
In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.
Fig. 1 is a flow chart illustrating a method for preparing waterborne polyurethane for microfiber leather according to an exemplary embodiment, where as shown in fig. 1, the method for preparing waterborne polyurethane for microfiber leather includes:
step (1): blending pentaerythritol and diisocyanate to obtain a first reaction solution, reacting the first reaction solution at 80-90 ℃ for 1-2 h, cooling to 20-25 ℃, adding ethylenediamine ethanesulfonic acid sodium salt into the first reaction solution, and reacting for 2-3 h to prepare the hydrophilic cross-linking agent, wherein the dosage ratio of the pentaerythritol to the diisocyanate to the ethylenediamine ethanesulfonic acid sodium salt is 1 mol: 4 mol.
In the reaction process, acetone can be added into the first reaction liquid to adjust the viscosity according to actual needs.
In a preferred embodiment, the diisocyanate is at least one of isophorone diisocyanate, IPDI, or 1, 6-hexamethylene diisocyanate, HDI.
When the diisocyanate is 1, 6-hexamethylene diisocyanate HDI, the reaction principle of the pentaerythritol, the 1, 6-hexamethylene diisocyanate HDI and the ethylenediamine ethanesulfonic acid sodium salt in the step (1) to generate the hydrophilic cross-linking agent is schematically shown in FIG. 2.
Step (2): blending 10-50 parts by weight of macromolecular dihydric alcohol, 2-6 parts by weight of micromolecular dihydric alcohol, 20-60 parts by weight of diisocyanate and 0.2-0.4 part by weight of catalyst to obtain a second reaction solution, reacting the second reaction solution at 60-90 ℃ for 3-4 hours, adding 1-5 parts by weight of micromolecular hydrophilic compound, continuing to react at 60-90 ℃ for 1-2 hours, cooling the second reaction solution to 20-30 ℃, slowly adding 1-15 parts by weight of hydrophilic cross-linking agent, reacting for 1-2 hours, adding 0.5-4 parts by weight of neutralizing agent, reacting for 0.5-1 hour, cooling the second reaction solution to 5-10 ℃, adding 100-250 parts by weight of deionized water, stirring at 2500-3000 r/min for 3-5 min, slowly dropwise adding 1-15 parts by weight of hydrophilic cross-linking agent, stirring at the speed of 2500-3000 r/min for 30min, and then carrying out distillation treatment to prepare the waterborne polyurethane for microfiber leather with the solid content of 25-40%.
Before blending, the macromolecular dihydric alcohol and the micromolecular dihydric alcohol are respectively subjected to vacuum pumping dehydration treatment for 3-5 hours at 120-130 ℃ so that the water content of the macromolecular dihydric alcohol and the micromolecular dihydric alcohol is less than 0.02%, the vacuum degree adopted in the vacuum pumping dehydration treatment process is-0.08-0.10 MPa, and other materials used in the experimental process are dehydrated in other modes.
In the reaction process, acetone can be added into the second reaction liquid to adjust the viscosity according to actual needs, so that the acetone in the second reaction liquid is distilled and removed after each component in the second reaction liquid is distilled.
In a preferred embodiment, the small molecule diol is at least one of ethylene glycol, 1, 4-butanediol, 2-methyl-1, 3-propanediol, diethylene glycol, and 1, 6-hexanediol.
For example, the small molecule diol may be 1, 4-butanediol or diethylene glycol, or a combination of 1, 4-butanediol and 2-methyl-1, 3 propanediol.
In a preferred embodiment, the macrodiol is at least one of polypropylene oxide polyol PPG, polytetrahydrofuran ether polyol PTMG, polyethylene glycol PEG and polycarbonate polyol PCD, and the small molecule hydrophilic compound is at least one of dimethylolbutyric acid and dimethylolpropionic acid.
For example, the macrodiol is polypropylene oxide polyol PPG or polytetrahydrofuran ether polyol PTMG, or the combination of polytetrahydrofuran ether polyol PTMG and polyethylene glycol PEG; the small molecular hydrophilic compound is dimethylolbutyric acid or dimethylolpropionic acid, or the combination of the two.
In a preferred embodiment, the catalyst is at least one of dibutyltin dilaurate, bismuth isooctanoate, and bismuth laurate.
In a preferred embodiment, the neutralizing agent is at least one of triethylamine, triethanolamine, tert-butylamine.
In order to facilitate the explanation of the preparation method of the waterborne polyurethane for microfiber leather provided by the present invention, a synthetic schematic diagram of the waterborne polyurethane for microfiber leather shown in fig. 2 is shown.
Fig. 3 is a flow chart illustrating a method for preparing microfiber leather according to an exemplary embodiment, wherein raw materials for preparing the microfiber leather comprise the waterborne polyurethane as described above. As shown in fig. 3, the preparation method of the microfiber leather comprises the following steps:
and (3): adjusting the solid content of the waterborne polyurethane for microfiber leather to be 20% -30%, and uniformly permeating the waterborne polyurethane for microfiber leather into the non-woven fabric by adopting an impregnation process, wherein the impregnation process comprises the following parameters: the pressure of the compression roller is 2-4 MPa, and the dipping temperature is 40-55 ℃.
In the embodiment of the invention, the impregnation process can adopt a tank body impregnation type, wherein the tank body impregnation type means that the non-woven fabric is completely soaked in the impregnation liquid, and the impregnation liquid uniformly enters the non-woven fabric through a guide roller and a roller in the tank body. The water-based polyurethane for microfiber leather enters the non-woven fabric mainly by means of permeation and rolling, the non-woven fabric is soaked in the groove and repeatedly runs, the impregnation liquid continuously permeates into gaps of the non-woven fabric, and the impregnation liquid permeates into the non-woven fabric after the non-woven fabric is rolled. After repeated padding, the waterborne polyurethane for the microfiber leather uniformly permeates into the non-woven fabric.
And (4): drying the non-woven fabric permeated with the waterborne polyurethane for the microfiber leather, putting the non-woven fabric into a NaOH solution with the concentration of 15-25%, opening the microfiber at 90-100 ℃ for 30-60 min, and performing after-treatment to obtain the microfiber leather.
And (4) dissolving the COPET fibers in the non-woven fabric fibers permeated with the waterborne polyurethane for the microfiber leather by an alkali reduction method, so that the fibers after fiber opening are refined.
In order to better illustrate the beneficial effects brought by the waterborne polyurethane for microfiber leather, the preparation method and the application thereof provided by the present invention, the following examples 1 to 3 are shown for illustration:
example 1
(1) Mixing pentaerythritol and 1, 6-hexamethylene diisocyanate HDI to obtain a first reaction solution, reacting the first reaction solution at 80-90 ℃ for 1-2 h, cooling to 20-25 ℃, adding ethylenediamine ethanesulfonic acid sodium salt into the first reaction solution, and reacting for 2-3 h to obtain the hydrophilic cross-linking agent, wherein the dosage ratio of the pentaerythritol, the 1, 6-hexamethylene diisocyanate HDI and the ethylenediamine ethanesulfonic acid sodium salt is 1 mol: 4 mol.
(2) Mixing 30 parts by weight of PTMG-1000, 3 parts by weight of ethylene glycol, 30 parts by weight of IPDI and 0.2-0.4 part by weight of dibutyltin dilaurate to obtain a second reaction liquid, reacting the second reaction liquid at 85 ℃ for 3-4 h, adding 1 part by weight of dimethylolpropionic acid to continue reacting at 80 ℃ for 1-2 h, then cooling the second reaction liquid to 20-30 ℃, slowly adding 10 parts by weight of hydrophilic cross-linking agent to react for 1-2 h, adding 0.7 part by weight of triethylamine to react for 0.5-1 h, cooling the second reaction liquid to 5-10 ℃, adding 200 parts by weight of deionized water, stirring at the speed of 2500-3000 r/min for 3-5 min, slowly dropwise adding 5 parts by weight of hydrophilic cross-linking agent, stirring at the speed of 2500-3000 r/min for 30min, and distilling, the aqueous polyurethane with the solid content of 30% for microfiber leather is prepared.
And (3): adjusting the solid content of the waterborne polyurethane for the microfiber leather to be 20%, and uniformly permeating the waterborne polyurethane for the microfiber leather into the non-woven fabric by adopting an impregnation process, wherein the impregnation process comprises the following parameters: the pressure of the compression roller is 2-3 MPa, and the dipping temperature is 40-55 ℃.
And (4): and drying the non-woven fabric permeated with the waterborne polyurethane for the microfiber leather, putting the non-woven fabric into a 15% NaOH solution, opening the microfiber at 90 ℃ for 30-40 min, and performing after-treatment to obtain the microfiber leather.
Example 2
(1) Mixing pentaerythritol and 1, 6-hexamethylene diisocyanate HDI to obtain a first reaction solution, reacting the first reaction solution at 80-90 ℃ for 1-2 h, cooling to 20-25 ℃, adding ethylenediamine ethanesulfonic acid sodium salt into the first reaction solution, and reacting for 2-3 h to obtain the hydrophilic cross-linking agent, wherein the dosage ratio of the pentaerythritol, the 1, 6-hexamethylene diisocyanate HDI and the ethylenediamine ethanesulfonic acid sodium salt is 1 mol: 4 mol.
(2) Blending 30 parts by weight of PPG-1000, 3 parts by weight of ethylene glycol, 25 parts by weight of HDI and 0.2-0.4 part by weight of dibutyltin dilaurate to obtain a second reaction liquid, reacting the second reaction liquid at 85 ℃ for 3-4 h, adding 2 parts by weight of dimethylolpropionic acid to continue reacting at 80 ℃ for 1-2 h, then cooling the second reaction liquid to 20-30 ℃, slowly adding 5 parts by weight of hydrophilic cross-linking agent to react for 1-2 h, adding 1.5 parts by weight of triethylamine to react for 0.5-1 h, cooling the second reaction liquid to 5-10 ℃, adding 150 parts by weight of deionized water, stirring at a speed of 2500-3000 r/min for 3-5 min, slowly adding 10 parts by weight of hydrophilic cross-linking agent dropwise, stirring at a speed of 2500-3000 r/min for 30min, and distilling, the waterborne polyurethane with the solid content of 35 percent for the microfiber leather is prepared.
And (3): adjusting the solid content of the waterborne polyurethane for microfiber leather to be 25%, and uniformly permeating the waterborne polyurethane for microfiber leather into a non-woven fabric by adopting an impregnation process, wherein the impregnation process comprises the following parameters: the pressure of the compression roller is 3-4 MPa, and the dipping temperature is 45-50 ℃.
And (4): and drying the non-woven fabric permeated with the waterborne polyurethane for the microfiber leather, putting the non-woven fabric into a NaOH solution with the concentration of 20%, opening the microfiber at 95 ℃ for 50-60 min, and performing after-treatment to obtain the microfiber leather.
Example 3
(1) Mixing pentaerythritol and 1, 6-hexamethylene diisocyanate HDI to obtain a first reaction solution, reacting the first reaction solution at 80-90 ℃ for 1-2 h, cooling to 20-25 ℃, adding ethylenediamine ethanesulfonic acid sodium salt into the first reaction solution, and reacting for 2-3 h to obtain the hydrophilic cross-linking agent, wherein the dosage ratio of the pentaerythritol, the 1, 6-hexamethylene diisocyanate HDI and the ethylenediamine ethanesulfonic acid sodium salt is 1 mol: 4 mol.
(2) Mixing 40 parts by weight of PTMG-2000, 4 parts by weight of ethylene glycol, 25 parts by weight of IPDI and 0.2-0.4 part by weight of dibutyltin dilaurate to obtain a second reaction liquid, reacting the second reaction liquid at 85 ℃ for 3-4 h, adding 2 parts by weight of dimethylolpropionic acid to continue reacting at 80 ℃ for 1-2 h, then cooling the second reaction liquid to 20-30 ℃, slowly adding 10 parts by weight of hydrophilic cross-linking agent to react for 1-2 h, adding 1.5 parts by weight of triethylamine to react for 0.5-1 h, cooling the second reaction liquid to 5-10 ℃, adding 150 parts by weight of deionized water, stirring at the speed of 2500-3000 r/min for 3-5 min, slowly dropwise adding 10 parts by weight of hydrophilic cross-linking agent, stirring at the speed of 2500-3000 r/min for 30min, and distilling, the waterborne polyurethane with the solid content of 35 percent for the microfiber leather is prepared.
And (3): adjusting the solid content of the waterborne polyurethane for microfiber leather to be 30%, and uniformly permeating the waterborne polyurethane for microfiber leather into a non-woven fabric by adopting an impregnation process, wherein the impregnation process comprises the following parameters: the pressure of the compression roller is 3-4 MPa, and the dipping temperature is 50-55 ℃.
And (4): and drying the non-woven fabric permeated with the waterborne polyurethane for the microfiber leather, putting the non-woven fabric into a NaOH solution with the concentration of 25%, opening the microfiber at 100 ℃ for 40-60 min, and performing after-treatment to obtain the microfiber leather.
The performance of the aqueous polyurethane and microfiber leather prepared in examples 1-3 was tested and compared with the performance data of conventional aqueous polyurethane and solvent polyurethane microfiber leather and leather, and the reference data of the performance tests are shown in tables one and two.
The table of the performance data of the waterborne polyurethane for microfiber leather provided in examples 1 to 3 is shown in table one:
Figure 902401DEST_PATH_IMAGE002
watch 1
Compared with various performance data of conventional waterborne polyurethane, the waterborne polyurethane for microfiber leather provided by various embodiments of the present invention shown in table one shows that compared with conventional waterborne polyurethane, the waterborne polyurethane for microfiber leather prepared by the present invention has the advantages of lower water absorption, better alkali resistance and higher storage stability.
The microfiber leather performance data provided in examples 1-3 are shown in table two:
Figure 740913DEST_PATH_IMAGE004
watch two
The comparison of various performance data of the microfiber leather provided by the embodiments of the invention and the solvent type polyurethane microfiber leather shown in the table II shows that compared with the solvent type polyurethane microfiber leather, the waterborne polyurethane microfiber leather for microfiber leather provided by the invention has better environmental protection property; compared with real leather, the waterborne polyurethane microfiber leather for microfiber leather provided by the invention has the advantages of lower apparent density, and better mildew resistance, chemical resistance and water resistance.
According to the relevant test data of the aqueous polyurethane for the microfiber leather provided by each embodiment shown in the table, the storage stability of the aqueous polyurethane for the microfiber leather synthesized by the embodiment of the invention is more than or equal to 6 months, the tensile strength is more than or equal to 10MPa, the elongation at break is 140% -190%, the water absorption (7 d) is less than or equal to 3%, the alkali resistance (25% NaOH, 100 ℃ and 1 h) is less than or equal to 4%, and the yellowing resistance is 5-grade.
Further, the performance of water absorption of the polyurethane for microfiber leather obtained by secondary chain extension provided in each embodiment of the present invention, the polyurethane obtained by single chain extension in acetone, and the polyurethane obtained by single chain extension in water are tested, and the water absorption line graphs of the polyurethanes under different chain extension modes are shown in fig. 4. As can be seen from fig. 4, the water absorption value of the aqueous polyurethane for microfiber leather obtained by the primary chain extension with acetone and the secondary chain extension in water provided by the embodiment of the present invention is significantly lower than the water absorption values of polyurethanes obtained by two other single chain extension methods, which indicates that the aqueous polyurethane for microfiber leather synthesized by the secondary chain extension process provided by the present invention has high storage stability and extremely high hydrolysis resistance.
According to the relevant test data of the microfiber leather provided by each embodiment shown in the table II, the water vapor permeability of the microfiber leather prepared by the embodiment of the invention is 480-610 mg/10cm2D, the tearing strength is 70.8-79.5N/mm, the yellowing resistance is 5 grades, the leather has extremely excellent water vapor permeability, aging resistance and wear resistance, can be completely used as a substitute for real leather, and has lower density and more excellent mildew resistance, chemical resistance and water resistance compared with real leather.
In conclusion, the aqueous polyurethane for microfiber leather provided by the invention and the preparation method and application thereof are characterized in that the aqueous polyurethane for microfiber leather is synthesized by a primary chain extension process in acetone and a secondary chain extension process in deionized water, the synthesized aqueous polyurethane for microfiber leather has high storage stability and extremely high hydrolysis resistance, and can solve the technical problems of poor stability and general water resistance caused by the fact that the aqueous polyurethane for microfiber leather is easy to gel.
While the invention has been described in detail in the foregoing by way of general description, and specific embodiments and experiments, it will be apparent to those skilled in the art that modifications and improvements can be made thereto based on the invention. Accordingly, such modifications and improvements are intended to be within the scope of the invention as claimed.
Other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. This invention is intended to cover any variations, uses, or adaptations of the invention following, in general, the principles of the invention and including such departures from the present disclosure as come within known or customary practice within the art to which the invention pertains. It will be understood that the invention is not limited to the precise arrangements described above and shown in the drawings and that various modifications and changes may be made without departing from the scope thereof.

Claims (10)

1. A preparation method of waterborne polyurethane for microfiber leather is characterized by comprising the following steps:
(1) blending pentaerythritol and diisocyanate to obtain a first reaction solution, reacting the first reaction solution at 80-90 ℃ for 1-2 h, cooling to 20-25 ℃, adding ethylenediamine ethanesulfonic acid sodium salt into the first reaction solution, and reacting for 2-3 h to prepare a hydrophilic cross-linking agent, wherein the dosage ratio of the pentaerythritol to the diisocyanate to the ethylenediamine ethanesulfonic acid sodium salt is 1 mol: 4 mol;
(2) blending 10-50 parts by weight of macromolecular diol, 2-6 parts by weight of micromolecular diol, 20-60 parts by weight of diisocyanate and 0.2-0.4 part by weight of catalyst to obtain a second reaction liquid, reacting the second reaction liquid at 60-90 ℃ for 3-4 hours, adding 1-5 parts by weight of micromolecular hydrophilic compound, continuing to react at 60-90 ℃ for 1-2 hours, cooling the second reaction liquid to 20-30 ℃, slowly adding 1-15 parts by weight of hydrophilic cross-linking agent, reacting for 1-2 hours, adding 0.5-4 parts by weight of neutralizing agent, reacting for 0.5-1 hour, cooling the second reaction liquid to 5-10 ℃, adding 100-250 parts by weight of deionized water, stirring at 2500-3000 r/min for 3-5 min, slowly dropwise adding 1-15 parts by weight of hydrophilic cross-linking agent, stirring at 2500-3000 r/min for 30min, and distilling, and preparing the waterborne polyurethane with the solid content of 25-40% for microfiber leather.
2. The method according to claim 1, wherein before blending, the macromolecule dihydric alcohol and the micromolecule dihydric alcohol are respectively subjected to vacuum dehydration treatment at 120-130 ℃ for 3-5 h, so that the water content of the macromolecule dihydric alcohol and the micromolecule dihydric alcohol is less than 0.02%, and the vacuum degree adopted in the vacuum dehydration treatment process is-0.08-0.10 MPa.
3. The method of claim 1, wherein the diisocyanate is at least one of isophorone diisocyanate (IPDI) or hexamethylene 1,6 diisocyanate (HDI).
4. The method according to claim 1, wherein the small molecule diol is at least one of ethylene glycol, 1, 4-butanediol, 2-methyl-1, 3-propanediol, diethylene glycol, and 1, 6-hexanediol.
5. The method according to claim 1, wherein the macrodiol is at least one of polypropylene oxide polyol, polytetrahydrofuran ether polyol, polyethylene glycol and polycarbonate polyol, and the small-molecule hydrophilic compound is at least one of dimethylolbutyric acid and dimethylolpropionic acid.
6. The method of claim 1, wherein the catalyst is at least one of dibutyltin dilaurate, bismuth isooctanoate, and bismuth laurate.
7. The method of claim 1, wherein the neutralizing agent is at least one of triethylamine, triethanolamine, and tert-butylamine.
8. The aqueous polyurethane for microfiber leather is characterized by being prepared by the preparation method of the aqueous polyurethane for microfiber leather according to any one of claims 1 to 7, wherein the storage stability of the aqueous polyurethane for microfiber leather is more than or equal to 6 months, the tensile strength of the aqueous polyurethane for microfiber leather is more than or equal to 10MPa, the elongation at break of the aqueous polyurethane is 140% -190%, and the yellowing resistance of the aqueous polyurethane for microfiber leather is 5 grade.
9. The application of the aqueous polyurethane for microfiber leather according to claim 8, wherein the aqueous polyurethane for microfiber leather is applied to the preparation of microfiber leather, and the preparation method of microfiber leather comprises the following steps:
adjusting the solid content of the waterborne polyurethane for the microfiber leather to be 20-30%, and uniformly permeating the waterborne polyurethane for the microfiber leather into the non-woven fabric by adopting an impregnation process, wherein the impregnation process parameters comprise: the pressure of the compression roller is 2-4 MPa, and the dipping temperature is 40-55 ℃;
drying the non-woven fabric permeated with the waterborne polyurethane for the microfiber leather, putting the non-woven fabric into a NaOH solution with the concentration of 15-25%, opening the microfiber at 90-100 ℃ for 30-60 min, and performing after-treatment to obtain the microfiber leather.
10. Microfiber leather prepared by the method of claim 9, wherein the microfiber leather has water vapor permeability of 480-610 mg/10cm2D, the tearing strength is 70.8-79.5N/mm, and the yellowing resistance is grade 5.
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